ELTRINGHAM, S K; BOYD, H. Aerial survey of wildfowl in the Highlands of Northern Scotland in the spring of 1959. Wildfowl, [S. l.], p. 103–106, 1959. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/155700. Acesso em: 18 dec. 2025.